A man carrying a shotgun opened fire at a busy US shopping mall, killing two employees of a skate shop and then himself as panicked shoppers ran for cover.
Five other people were injured in the incident in suburban Baltimore, Maryland, yesterday.
Police were still trying to determine the identity and motive of the gunman who killed a man and a woman, both in their 20s, at a skate shop called Zumiez on the upper level of the Mall in Columbia, a suburb of both Baltimore and Washington.
Witnesses described hearing gunshots and screaming as panicked shoppers ducked into nearby stores and hid behind locked doors.
Many found cover in stockrooms and barricaded themselves until the arrival of police, who searched store to store. By late afternoon, the mall had been cleared of shoppers and employees.
Howard County police chief William McMahon said at a news conference that authorities had difficulty identifying the gunman because of concerns he might be carrying explosives and were proceeding with an "abundance of caution".
He said: " We do not know yet what caused the shooting incident. We do not have a motive."
Someone called police at around 11.15am local time to report a shooting at the mall.
Officers responded to the scene within two minutes and found three people dead - including the apparent gunman lying near a shotgun and ammunition - either inside or outside the shop, which sells skateboards, clothing and accessories.
Mr McMahon said police were confident there was a single gunman.
Howard county general hospital said it had treated and released five patients. One patient had a gunshot wound, while at least three other patients suffered other injuries.
The mall is at the centre of the town and usually opens at 10am on Saturdays. It was filled with shoppers and employees when the shots rang out before noon.
Joan Harding of Elkridge, Maryland, was shopping with her husband, David, for a tiara for their granddaughter's 18th birthday. She said she heard something heavy falling, followed by gunshots and people running.
"My husband said, 'Get down!' and the girl that worked in the store said, 'Get in the back,'" Mrs Harding said. That is where they hid until police searched the mall and signalled it was safe to leave.
The mall was closed to the public as police looked in each store for people who might still be hiding, Mr McMahon said. It will remain closed at least through the night.
Mr McMahon said it was not clear whether the gunman and victims knew each other. He said officers did not fire any shots when they arrived at the scene.
Asked if the gunman shot himself, the chief answered: "That is certainly what it appears to be at this point."
People were directed out of the mall and into a car park, where some boarded a bus and others walked toward their cars. Some people were seen crying.
Allison Cohen, who works at the clothes shop Lucky Brand Jeans, said she always felt safe at the mall.
"I truly never thought something like this would ever happen here," she said. "It's really, really shocking."
Police later said they disabled crude attempts at explosive devices that were found in a bag carried by the gunman.
A news release says investigators searched the gunman's bag inside the store where two employees were shot.
They found and disabled what they described as "crude devices that appeared to be an attempt at making explosives using fireworks".
The mall will remain closed today and police will use dogs to search it overnight, which is standard procedure.
Police say they have tentatively identified the gunman but are declining to identify him while they follow up on leads.